NAME

       chrt - manipulate the real-time attributes of a process

SYNOPSIS

       chrt [options] prio command [arg]...
       chrt [options] -p [prio] pid

DESCRIPTION

       chrt  sets  or  retrieves  the real-time scheduling attributes of an existing pid, or runs
       command with the given attributes.  Both policy (one of SCHED_OTHER, SCHED_FIFO, SCHED_RR,
       SCHED_BATCH, or SCHED_IDLE) and priority can be set and retrieved.

       The  SCHED_BATCH  policy  is  supported  since  Linux  2.6.16.   The  SCHED_IDLE policy is
       supported since Linux 2.6.23.

       The SCHED_RESET_ON_FORK flag for policies SCHED_RR and SCHED_FIFO is supported since Linux
       2.6.31.

OPTIONS

       -a, --all-tasks
              Set  or  retrieve  the scheduling attributes of all the tasks (threads) for a given
              PID.

       -b, --batch
              Set scheduling policy to SCHED_BATCH (Linux specific).

       -f, --fifo
              Set scheduling policy to SCHED_FIFO.

       -i, --idle
              Set scheduling policy to SCHED_IDLE (Linux specific).

       -m, --max
              Show minimum and maximum valid priorities, then exit.

       -o, --other
              Set policy scheduling policy to SCHED_OTHER.

       -p, --pid
              Operate on an existing PID and do not launch a new task.

       -r, --rr
              Set scheduling policy to SCHED_RR (the default).

       -R, --reset-on-fork
              Add SCHED_RESET_ON_FORK flag to the SCHED_FIFO or SCHED_RR scheduling policy (Linux
              specific).

       -v, --verbose
              Show status information.

       -h, --help
              Display usage information and exit.

       -V, --version
              Display version information and exit.

USAGE

       The default behavior is to run a new command:
              chrt prio command [arguments]

       You can also retrieve the real-time attributes of an existing task:
              chrt -p pid

       Or set them:
              chrt -p prio pid

PERMISSIONS

       A  user  must  possess CAP_SYS_NICE to change the scheduling attributes of a process.  Any
       user can retrieve the scheduling information.

NOTES

       Only SCHED_FIFO, SCHED_OTHER and SCHED_RR are part of POSIX  1003.1b  Process  Scheduling.
       The other scheduling attributes may be ignored on some systems.

AUTHOR

       Written by Robert M. Love.

COPYRIGHT

       Copyright © 2004 Robert M. Love
       This  is  free software; see the source for copying conditions.  There is NO warranty; not
       even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

SEE ALSO

       taskset(1), nice(1), renice(1)

       See sched_setscheduler(2) for a description of the Linux scheduling scheme.

AVAILABILITY

       The  chrt  command  is  part  of  the   util-linux   package   and   is   available   from
       ftp://ftp.kernel.org/pub/linux/utils/util-linux/.